Dr. Ben Carson's sudden swan dive in the Republican presidential polls is the result of his lackluster grip on foreign policy issues — and Sens. Marco Rubio of Florida and Ted Cruz of Texas are quickly picking up the slack, veteran GOP consultant and policy advisor Karl Rove tells Newsmax TV.

"Dr. Carson is an admirable person. He's got great moral character. He's a wonderful human being, he's a friend of mine, but he has suffered to the degree that foreign policy has begun to sort of rise up in this campaign," Rove said of the retired pediatric neurosurgeon in an interview Thursday on "Newsmax Prime" with J.D. Hayworth.

"He has suffered. His numbers have gone down because he's not shown a sure foot in this, in dealing with these questions."

Questions about Carson's abilities when it comes to foreign policy have been raised throughout his campaign, however those concerns came to a head last week, when one of his advisors spoke with The New York Times.

"Nobody has been able to sit down with him and have him get one iota of intelligent information about the Middle East," said Duane Clarridge, a former CIA agent and a top adviser to the physician on national security.

Previously, when Carson himself appeared on "Fox News Sunday" earlier this month, he failed to say which countries he would call on to form a coalition force against the Islamic State.

"[Carson's] dropped and the two people who've risen equally in Iowa have been Marco Rubio and Ted Cruz. Ted Cruz has done a very smart game in Iowa. I would not be surprised to see him win it. I've been thinking that for a number of weeks," Rove said.

"My friends and confidants in Iowa say he has been doing really well in organizing, but we're going to have a very long contest here. It is very unclear who's going to be the nominee."

"We have a lot more states that are voting early, a lot more delegates that are proportional, 28 states will have voted by the 12th of March and of those, only one – South Carolina – is winner take all. All the states in that period except for those four states that are allowed to vote in February have to be proportional and three out of four of the states who vote in February have elected to be proportional."

That means the GOP will end up with delegates "split all over the place," Rove predicted.

"And what's going to really matter then [is] who is left standing when we start going to the winner-take-all primaries on the 15th of March."

"The ides of March will begin - wasn't good for Caesar – it's not going to be good for some other candidates as we begin to vote winner take all."